<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        function Judge(num) {
            for (var i = 2; i < num; i++) {
                if (num % i == 0) {
                    return num + '不是一个素数'
                }
            }
            return num + '是一个素数'
        }
        alert(Judge(prompt('请输入一个大于1的整数：')))
    </script>
</body>

</html>